Raabe O G, Book S A, Parks N J
Health Phys. 1983;44 Suppl 1:33-48. doi: 10.1097/00004032-198306001-00002.
The life-time tumor dose-response relationships observed in beagles injected with 226Ra or fed 90Sr at the University of California, Davis, provide a basis for understanding the induction of bone cancer for these bone-seeking radionuclides and for scaling to people. In these studies 385 dogs were exposed to graded dosage levels of 90Sr and 243 dogs were exposed to graded dosage levels of 226Ra with a total of 159 unexposed controls. The results show different dose-response relationships for bone cancer for the two radionuclides based upon the gravimetric average dose rates and cumulative doses to bone. These relationships were found to be well represented by three-dimensional log-normal dose-response surfaces that yield risk as a function of average dose-rate and time after beginning of exposure. All dose-rates suggested a 100% risk at some later time post-exposure but the time required to reach a given level of risk was long for low dose rates so that there exists a practical threshold in that at lower dose rates individuals may die spontaneously from causes associated with natural aging prior to the expected appearance of radiogenic cancer. The risks to people at various 226Ra body burdens (average skeletal dose rates) are estimated based on the model.
在加利福尼亚大学戴维斯分校，给比格犬注射226镭或喂食90锶后观察到的终生肿瘤剂量反应关系，为理解这些亲骨性放射性核素诱发骨癌以及按比例推算人类情况提供了依据。在这些研究中，385只狗暴露于分级剂量水平的90锶，243只狗暴露于分级剂量水平的226镭，共有159只未暴露的对照犬。结果表明，基于骨的重量平均剂量率和累积剂量，两种放射性核素诱发骨癌的剂量反应关系不同。这些关系被发现可以很好地用三维对数正态剂量反应曲面来表示，该曲面将风险表示为平均剂量率和暴露开始后时间的函数。所有剂量率都表明在暴露后的某个较晚时间风险为100%，但低剂量率达到给定风险水平所需的时间很长，因此存在一个实际阈值，即在较低剂量率下，个体可能在预期的放射性癌症出现之前因与自然衰老相关的原因自然死亡。基于该模型估算了不同226镭体内负荷（平均骨骼剂量率）情况下对人类的风险。
